1. Field of the Invention
The present invention relates to inflatable airbags for protecting vehicle occupants during collision events. More specifically, the present invention relates to an airbag module configured to be installed in a support pillar of a vehicle.
2. Description of Related Art
Inflatable airbags enjoy widespread acceptance as passive passenger restraints for use in motor vehicles. Airbags have built a reputation of preventing numerous deaths and injuries over years of development, testing, and use. Studies show that in some instances, the use of frontally placed vehicular airbags can reduce the number of fatalities in head-on collisions by 25% among drivers using seat belts and by more than 30% among unbelted drivers. Other statistics suggest that in a frontal collision, the combination of a seat belt and an airbag can reduce the incidence of serious chest injuries by 65% and the incidence of serious head injuries by up to 75%. These numbers and the thousands of prevented injuries they represent demonstrate the life-saving potential of airbags and the need to encourage their use, production, and development.
In part as a result of benefits such as those described above, automakers are now required to install airbags in most new vehicles manufactured for sale in the United States. Many automobile manufacturers have turned this airbag technology requirement into a marketing tool. Enticed by the promise of added safety, vehicle purchasers frequently seek out vehicles with sophisticated airbag systems.
Airbags are often installed in the steering wheel and in the dashboard on the passenger""s side of a car. These airbags are often large and thick because airbags are used for the primary deceleration of a vehicle occupant. In a large percentage of collisions the occupant is accelerated forward through the vehicle. Frontal airbags are generally constructed to inflate toward the vehicle occupant, often with significant force. Airbag systems are generally designed to protect an occupant in a specific space within the car in a specific set of predicted positions. When a vehicle occupant is not positioned in a predicted position, deployment of the airbag may cause injury to the occupant.
Frontal airbags are generally housed within the dashboard, steering wheel, or other similar interior panels of a vehicle, and are covered by a trim cover panel. The trim cover panel covers the compartment that contains the airbag module. Such airbag covers are typically made of rigid plastic, and are configured to open by the pressure from the deploying airbag. During deployment of the airbag, it is preferable to retain the airbag cover in at least partial attachment to the vehicle to prevent the airbag cover from flying loose in the passenger compartment. If the airbag cover were allowed to detach and freely move into the passenger compartment, it could cause injury to a passenger.
Airbags are generally linked to a control system within the vehicle that triggers their initiation when a collision occurs. This control system is often referred to as an electronic control unit (or xe2x80x9cECUxe2x80x9d). The ECU includes a sensor that continuously monitors the acceleration and deceleration of the vehicle. This information is sent to a processor which processes it using an algorithm to determine if a deceleration experienced by the vehicle is a collision or not. If this accelerometer measures an abnormal deceleration, such as one caused by a collision event, it triggers the ignition of an airbag inflator.
When the processor of the ECU determines, based on a set of pre-determined criteria, that the vehicle is experiencing a collision, the ECU transmits an electrical current to an initiator assembly. The initiator assembly is in turn connected to an inflator that is coupled to the airbag module. The initiator activates the inflator. An inflator is a gas generator that typically uses a compressed or liquefied gas or mixture of gases, a solid fuel, or some combination of the two, to rapidly generate a large volume of inflation gas. This inflation gas is then channeled, often through a segment of specialized tubing called a gas guide, to the airbag. The gas inflates the airbag, allowing it to absorb the impact of the vehicle occupants and thus prevent possible injury.
Following the activation of the airbag system and the deceleration of any vehicle occupants, the airbags rapidly deflate to release the vehicle occupants. Some airbags may be fully inflated within 50 thousandths of a second, and subsequently deflated within two tenths of a second.
As experience with the manufacture and use of airbags has progressed, the engineering challenges involved in their design, construction, and use have become better understood. First, most airbag systems are designed to rapidly inflate and provide a cushion in front of or alongside an occupant based on a presumption that the occupant will be in a predetermined position. Problems have been noted to occur when the occupant is xe2x80x9cout of positionxe2x80x9d with regard to this presumed placement when a collision event occurs and the airbag deploys. Similarly, problems may occur when the occupant, though possibly at first in the predicted position, strikes a glancing blow to the airbag, and is then deflected out of the airbag before proper deceleration can occur.
Other out-of-position injuries occur when an occupant is positioned within the inflation path of the airbag. In such cases, the occupant may be struck by the airbag when it inflates, in some cases causing substantial injury to the occupant. Airbags currently used in the art inflate with significant force in order to be inflated and in place in a very short period of time. Part of the problem may be attributed to the fact that most airbags inflate directly toward the occupant.
Additional problems in airbag use involve effective coverage of potential impact surfaces of a vehicle interior by airbags. Many of the known airbags effectively protect the occupant from contact with regions of the dashboard, the windshield, and often, the steering wheel. One area more difficult to protect traditionally has been the vehicle""s A-pillar. This rigid pillar carries potential to cause serious injury to a vehicle occupant during a collision event.
Other problems faced in the development and use of airbags include costs encountered in providing a proper housing and attachment for airbags. Many dashboard- and steering wheel-mounted airbags require the use of housings separate from the structure of the vehicle itself for convenient use, thus raising the cost of use of the airbags. It would be an advancement in the art to provide an airbag mounted and housed within the structure of the vehicle to reduce the cost of airbags.
Finally, with airbags mounted in dashboards, doors, steering wheels, etc., considerable damage is often caused to the mounting panel by deployment of the airbag. Specifically, in dashboard-mounted systems, deployment often causes sufficient damage to the instrument panel of the vehicle to merit complete replacement.
Accordingly, the need exists for a pillar-mounted frontal airbag system to better protect a vehicle occupant. Such a system could protect the vehicle occupant in a wide variety of collision events, including those requiring better shielding of the A-pillar. Specifically, it would be an advancement in the art to provide a pillar-mounted frontal airbag suitable for mounting in a vehicle in the A-pillar of the vehicle, the airbag module requiring reduced housing and attachment means and reducing the need for instrument panel replacement after airbag deployment. Finally, it would be an advancement in the art to provide an airbag which reduces the incidence of out-of-position injuries by deploying first along the dashboard of a vehicle, and then deploying toward the occupant, thus contacting the occupant (if at all) with greatly reduced inflation force. Such a device is disclosed and claimed herein.
The apparatus of the present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available airbag modules. Thus, it is an overall objective of the present invention to provide a pillar-mounted airbag module for protecting a vehicle occupant.
To achieve the foregoing objective, and in accordance with the invention as embodied and broadly described herein in the preferred embodiment, a frontal airbag module for protecting a vehicle occupant is provided. The airbag module may include an inflator, and an airbag cushion having an inflation orifice, wherein the inflator is coupled to the airbag cushion at the inflation orifice. The airbag module is adapted to be installed into a side pillar of a vehicle. The airbag cushion is in some embodiments sufficiently elongated in shape such that when the airbag is installed in a side pillar of a vehicle, initiation of the inflator deploys the airbag cushion between a vehicle occupant and a structure of the vehicle.
The airbag cushion may be elongate in shape. Specifically, the airbag cushion may be made elongated in shape such that when it inflates, it reaches from its site of installation, such as the A-pillar, to the center of the vehicle. Additionally, the inflation orifice may be placed at an end of the airbag which is used for mounting the airbag.
The airbag cushion may be constructed of multiple panels. Specifically, the cushion may comprise an upper panel, a lower panel, and a central panel. The central panel of such an airbag cushion may additionally include an inflation orifice. This inflation orifice may simply comprise a narrowed throat region of the airbag.
According to the present invention, the frontal airbag module may include an airbag cushion configured to be a driver""s side airbag cushion. Such a module would be installed in the A-pillar nearest the seat of the vehicle driver. Alternatively, the frontal airbag module of the present invention may include an airbag cushion configured to be a passenger""s side airbag cushion. Such a module would be installed in the A-pillar nearest the seat of the front-seat passenger. The invention may also be made suitable for use in the other pillars of a vehicle, such as the B, C, and D pillars.
Additionally, the frontal airbag module of the invention further may comprise at least one tether to assist in the proper positioning of the airbag cushion upon inflation. Tethers may be positioned internally within the airbag cushion to direct its inflation direction, path, and shape, as well as externally to further direct the inflation path and configuration, as shown in FIG. 2.
The frontal airbag modules of the invention also include an airbag inflator for inflating, and thus deploying, the airbag cushion briefly described above. Such an inflator may be substantially cylindrical in shape so as to be most easily accommodated within the pillar of the vehicle. Additionally, the airbag inflator may be either a single-stage airbag inflator or a dual-stage airbag inflator.
The pillar-mounted frontal airbag module of the invention may also include a trim panel. The trim panel is configured to be attached to the other components of the airbag module as well as to the pillar of the vehicle to which the assembly is to be mounted. This trim panel encloses the airbag and inflator. The trim panel also serves to allow the airbag to be integrated into the vehicle in a visually pleasing manner, since the trim panel can be constructed of materials similar in color and texture to those used in the interior of the vehicle in which the airbag is to be installed.
The trim panel of the airbag module is constructed to release the airbag upon initiation of the inflator, thus deploying the airbag into the cabin of the vehicle in a position in front of a vehicle occupant. This may be accomplished in several ways. The trim panel could be made releasable by equipping the trim panel with hinges and a releasable latch. Alternatively, the trim panel could be constructed so as to predictably rupture in such a manner that the airbag would be properly deployed. This could be accomplished by providing a trim panel with frangible portions such as a scored or perforated internal surface.
In addition to the features discussed above, it should be noted that the airbag module of the present invention is unique in its configuration, mounting location in a vehicle, and deployment method. Specifically, the airbag is configured to be installed completely within the A-pillar of a vehicle. The inflator and airbag nest within the A-pillar, and are releasably enclosed by the trim panel. By including the inflator within the A-pillar, the need for a gas guide or other similar intermediate tube between the inflator and the airbag itself is avoided. This may reduce the expense associated with manufacturing and installing the airbag.
In addition to the above-mentioned benefits, installation of the airbag module completely within the A-pillar allows increased flexibility in the design of the instrument panel, steering wheel, driver""s side and passenger""s side of the vehicle. Specifically, by removing the airbag modulexe2x80x94both the airbag cushion and the airbag inflatorxe2x80x94from the dashboard, space is left to add either additional features to the dashboard/instrument panel/glove compartment of the vehicle or to add greater flexibility to the design of the dashboard. Furthermore, the overall mass of inflator portion of the airbag module may be reduced in this scenario since the structure of the A-pillar eliminates the need for attachment brackets and additional securing reinforcements.
In addition, by removing the airbag from the instrument panel, the costs associated with repairing a vehicle after airbag deployment may be reduced by lowering the need for instrument panel replacement due to damage caused by airbag deployment.
The pillar-mounted airbag of the invention deploys when activated by a control unit linked to the inflator of the module. The airbag inflator is directly linked to the airbag cushion of the module. When activated, the inflator begins rapidly producing inflation gas, thus creating high internal pressures within the airbag module. At this point, the trim panel releases the airbag, either by opening along a hinged region, or by rupturing in a predictable manner. In either case, the folded airbag is deployed, thus allowing it to be inflated by the pressurized inflation gas being rapidly produced by the inflator.
The airbag cushion of the present invention is novel in that it is configured to deploy first laterally along a windshield toward the center of the vehicle in which it is installed, and then to subsequently inflate toward the occupant. More particularly, the airbag first inflates toward the center of the vehicle along the dashboard. Next, the airbag begins to expand outwardly toward the back of the vehicle. As this expansion continues, the airbag is deflected away from the windshield, and begins to swing outwardly away from the windshield. This, in addition to the expansion of the cushion backward toward the occupant, assists in properly positioning the cushion for use.
The airbag cushion of the invention is thus positioned in the A-pillar to deploy to prevent a vehicle occupant from striking a surface in front of the occupant such as a dashboard, steering wheel, or windshield. By deploying in this manner, much of the initial force with which the airbag is inflated is directed along a vector away from the occupants of the vehicle. This function reduces the possibility of airbag-caused injury to the vehicle occupant, and may additionally reduce the severity of such injuries when they do occur. This configuration further acts to prevent out-of-position injuries to a vehicle occupant by sweeping toward the occupant, as well as by being inflated toward the occupant more gently. Finally, the airbag module of the invention improves the coverage of the A-pillar by preventing possible occupant contact with the A-panel during a collision event.
These and other objects, features, and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.